Jig for winding spherical coils



, Feb. 5, 1946. I N, T, VOL K v 2,394,028 JIG FOR WINDING SPI-IERICAL c011,; v

Filed Nov. 3; 1 44 1 INVENTOR. I

mgmmmg QLAS T. VOLSK I ATTORNEY Patented Feb. 5, 1946 v umr121)-; STAT-ES PATENT OFFICE;-

r 1e;s94,0zs '7 I a I H I JIG FOR"W'-INDINGSPHERICALYJUILS l Nicholas T. =Vol'sk, Spring Lake, J.,assig-nor to i the Government of vthe United vStates of America, asrepresentedby the Secretary'dfWar I Appllcation November 3.19144, SBfiaI NOJ 561,800

1 reclaims. (01.242 -9 V r Granted im'der'the act of Mar ch stress; s v amnacanpmzso, 1928;-'3-70 olouim The invention described-hereidmay beimanun iactured and .used by or :for "the; Government-for governmental purposes, without :the :payment to melof any royaltythereo y Y .i This invention relates to spherical icoils vused in radio tuning circuits- ;'Ihe invention discloses the structure and the-method of v snakin .the spherical coils. I

,It is well known in .theiradio 'art zthatthe sphericalcoils when used in connection .withithe varioineters are much more effective than the cylindrical coils because the spherical coil :rotor. may .be-coupled. much closer to the cylindrical stator ofthe variometer, enabling one to span wider frequency band with the variometers of @hist'yDe. Altho this advantage of ithelsphericalcoilschas been recognized, their :use haslbeen somewhat limited because no simple manufacturing :methods. were available, and, as arconseduence; the majority of variometers use either lcylindricalrptors, ion-rotors which only attempt t'o approach the surface delined by aperfect sphere.

.The invention discloses a simple method of making the. spherical "coils, an: auxiliary jig used for Winding theccoils, and a .coil..form whichcmay be used with the jig. l i a .In theprior art, the spherical coils were wound either directly on the coil forms orv on jigs which required subsequent; cutting of. wire for removal ofithecoil wire from the'ji 'Ihelatter method is disclosed inan application forv patent of Edward E. Combs, 552,859 filed September 6; 1944..

When the. coils are wound directly onothe -coil terms because of thelimited number otiviresupports provided along the spherical surface crane coil, the wire does not follow the spherical surface but instead'bends at thesupports and-iollows a path of a cord forming thetwozadiacent supports; Coils of this type cannot be-coupled closely to the outside cylindrical coil of-the variometer because they do. not possess the desired spherical form, In thesecond methodof winding coils, i. e., with the aid of 'a lie and subsequent-cutting of wire. the ,process is rather laborious, requiressoldering of the wires, and. the soldered joints produce spurious radiations at U. H. F. increasing the losses encountered in the coils.

.The invention discloses amethodand apparatus for Winding a coil possessing a substantially spherical ,surfacesand without anyisoldered joints. The method of winding the coil may be considered an i provement on the method disclosed inlthe previously mentioned. application of Combs disclosed invention eliminates transferring, cutting, and subsequent'soldering of the wire taught on the coil-forms, the wiresforminga portion of 'a-substantially perfect sphere. I

Another object of this inven-tion i tc provide acoil term with identicalrwire-supporting-bridges disposed along a l-helix, the helical ipath corresponding to the pitchrof the coil. v a ;The novel -features which -I- believe to be characteristic ofsmy invention areset forth with parti culariity in the appended-claims invention itsel-f however, both as to its organizationand methodrof operation, togetherwith the obiects and advantages thereof, may best bemnderstoodin connection with -thefollowing description and accompanying-drawing in which, V

. Fig. .1 isanexploded perspective view of a jig forwindin glthe coil, anda-perspective view of; the coil form-rused for supporting the wire. Y Fig.2 is-a cross-sectional view-of the'jig'taken alongline 2-2 illustrated in Figure l. v.rFignl-is-a-plan View of thewound coil.

Referring to Figure .1, the "coil form consists of a plurality of ceramic bridges in with arched and grooved wire-supporting surfaces i8 andiprojecting teeth 12,14, which fit into recesses H, l3, etc, in a ring Hi. 'The ring is preferably made of-plastic material offering low radio frequency loss}; .The bridges in are identical to each other, and in-order to obtain the desired wire-pitch the recesses [Land -l'3gare disposed along a helical path corresponding tothe pitch desired in the coil. Theme of the supports with the identically positioned grooves l8 results. in minor distortion cr -the coil surface; however, the departure tor-the produced surfaceirom a perfectsphere isso in significant that the advantage gai-nedzby having identical ceramic pieces become more important than the created distortion of the surface. The coil form-having ceramic bridges and a ring made of plastics produces :a coil form which can withstand mechanical shocks better than thecoil for-mssmadecompletely of ceramics, while the ceramic bridges resist high temperature encountar-ed at heavy electrical loads. The jig may be used neverthelessw-ith all ceramic coil forms, or terms made of any other-suitable material.

'Ihjig includes a mandrel 20 held by a chuck ofa latheforturning it; a wedge plate 22 integral with'the mandreland having a plurality of chamfeted or beveledWedge-forming surfaces My a provided with a wing nut 21, sisting ofa wedge plate 36 and a plurality of legs 3|, with oblong cross-sections and equippedwith drum 26 used for holding ring 16 in; sliding engageinent with the drum; and a threadedrodifl A spider 29, conthe projecting dovetails 32 on the outer surfaces 'of the legs; is used for holding six wire supports between the wedge plates 22 and 30. The wire supports hold the wire during the wire-winding operation and fit into the recesses betweenthe bridges 16. The form is assembled by sliding ring I6 over drum 26. In' order to facilitate proper alignment of the drum withthe'ring, the

drum and the ring are provided with an aligning groove 34, and a wedge 36 respectively. ;The

wedge plates 22 and are provided with fiat springs 31,38, 39 and 40 which automatically align the bridges with respect tothe-wire sup.-

ports 25, as it will be explained presently. Upon e: sliding the coil form over drum 26, spider 29 is 1 slipped over ring [6 with the wire supports 25 mounted on the dovetails 32 priorto,its place}- ment over ring l6, as is illustrated more fully in Figure 2. The'wire supports, as well as the legs,

are so dimensioned that the supports engage the beveled portions 24 and 33 of the wedge plates and the beveled portions of the dovetails 32'wh'en V the wing nut 21 is tightened. The dovetail joint.

between the dovetail projections '32, and the dovetail recesses 35 in the wire supports are dimensioned so as to form a relatively loose joint or allowing the beveled portions 24 and 33 'of the wedge plates to raise the wire suppo rts' slightly above the surfaces of bridges Ill when wing nut 29 is tightened. A positive, rigid engagement for example, of. red color, is alwaysaligned with {red strip 59, wedge 36, and indentation 66 on the ring, etc. Accordingly, the proper procedure of r assembling the jig consists of mounting the coil 5 form on the drum, dovetailing the wire supports 1 onto the spiderwith the color combinations on the wire supports matching the color combinaltions on' the spider, slipping the spider with the wire supports upon it over the coil form,with the red color strip56fitting over groove 60 of the coil,

,and tightening nut 29 thereafter. Since the 1at-' eral positions of the bridges between 'the. wedge plates are all difierent, proper alignment of the "grooves may be obtainedonly when the coil form r and the'wire supportsare placed according to the Proper alignment of :the' elements may be improved stillfurther by V providing awedge'on the lower portion of leg'3l previously described order.

having red mark 59, this wedge matching groove 60 on the ring I 6. The flat springs 31 through 40 engage the bridges 46 and 58, and'holdthe coil form in an elastically adjustable relationship with respect to the wire supports to take care-of minor 7 bridge be slightly out; of alignment with the 3 grooves in the'wire supports,

The center portion of wire support'45 is provided with a projection 49 'for introducing a bend joint between spider 29 and the wedge plate 22 is 7 thus obtained. The spacing ibetween'the'wedge' plates at fthisf instant is 1 such that the bridges l0 do not engage eitherof the wedge plates directly, but are positioned in the desired 7 relationship with respect to thewire supports by means of the previously-mentioned flatsprings3'l through 40, as illustrated more clearly'inl ig ure 2. Theen'tire jig is now ready for winding the" coil. The winding process is'started by clamping the starting end of the coil' wire by 7 means of a clamp 44, and starting thelathe.

The reason for providing a recess 34 ands.

wedge 36 for positioning the coil forni' always in the indicated relationship with respect to the wedge plates, is as follows: since all bridges are identical, the pitch is obtained, as mentioned previously, by shifting the position of the successive bridges on ring I6, for example: the upper bridge 46 may occupy the extreme left position on ring I6, and bridge 48 the extreme right position; 'fAll The separation of the jig from the coil is accom wire supports 25 are provided with grooves 56 which also have proper pitch, and, therefora ar'e the surface of the supports so'that the wire, after it hasibeen' clamped by clamp 44, will'follow the not identical to each other, but "are made with'a 5|, Fig. 3 in the wire of the coil; whichiis neces-,

sary for providing clearance between" the wire and shaft 6'Igof the coil; Projection 49' is provided'at' its base with a cross-groove 53 whichincre'ases the pitch of'the wire path fOIithB length of the projection, this increasebeing such as to transfer 7 the wire when'it reaches thev center-turn to the next groove 18 on the ceramic suppor't lo fthus separating the wire pathinto two spaced symmetrical'halves and enlarging theseparationbetween the two adjacent'center-turns ofjthejcoil. Upon winding of the wire, it is' clamped down by means of a clamp 62, the arcuate' metal strips64 and 66 of which are equipped with rubber pads 6|, 63, the pads fitting tightly over the diametri-f c'ally opposite, outer turns of the wire, and holding ithem'tightly against the bridges which prevents any loosening of the wire during any subsequent operations.

plished by unscrewing thewing nut 21 which'results in sliding of the wire supports along the beveledsurfaces 24 and 33,.thus relieving the pressure exerted by the wire on the wire supports and transferring this pressure to the bridges. Since the wire supports are now onlyin loose engagement with the spider, the spider maybe slipped out from under the supports.

properly pitched, continuous, helical path. This 7 being the case, the spherical supports must be placed in a predetermined orderof rotation with V respect to the coil form in order to match its pitch. Thus the wire support 52 must be positioned between the bridges 46 and 47; thewire support 54 must be positioned between the bridges 48 and 46, etc. To facilitate'proper orientation of the wire supports with respect to. the coil form the supports are provided with-color combinations, illustrated as cross-hatched strips 56 and '51, etc. which match the corresponding strips 59, I2; etc. on the spider. Strip 56-which maybe,

The'wire supports may nowbe slippedout of engagement with the'coil frame and the wire by sliding them either to the left or to the right on the ring and by turning themaround theouter edges of the ring. 'Theaxial dimension of, the ring is so proportioned that thewire supports may pass through the openings formed between the outer turns of the coil-and the upper edgesof the ring when the supports are turned or rotated around these edges; When the wire supports are 'removed, the two ends of the wire are connected to metal shafts 65, 61 by means of lugs 68, 69, and nuts 19,.1l, as illustrated more clearly in Figure 3,- which completes the winding process of the coil.

= From the description ofi=the jig and of the ;coil form, it follows that all stresses occurringdur ing the winding operation are imposed directly on'the wire "supports, rather than the coil form,- ,thecoil for-hi floating within-the jig at this time. In some-instances, when the'wire is especially heavy, this may be a very desirable feature since lighter coil forms may be used for-supportingthe wire after the winding operation has been completed. Once the wire has'been preformed by means of the jig, it may be held in fixed position by every light'coil form since the main stresses obviously occur during the winding operation. Besides re ducing-the total weight of the variometer, the lightcoilforms reduce the radio frequency loss introduced by the variometer.

'Ihewire support fis'illustrated asa segment of a sphere' truncated on four "sidesjso as to-fo'rm a solid having an oblong base, and four fiat sides perpendicular to the basetoppedbyaspherical su-rface,-the centerof which is on a line perpendicular to the base at the geometric center of said base. It is obvious that the spherical surface with one exception must be retained in all cases, but all the remaining surfaces may have different shape and relationship with respect to each other than that illustrated in the drawing. The remaining surfaces must satisfy onlyone requirement: they should hold the 0011 form in a sufficiently fixed relationship with respect to the wire supports during the winding operation of the coil, and should be easily removable during the dismantling operation of the jig. Where the pitch of the wire is very large, the departure of the bridges from a perfectly spherical surface may be such as to warrant a corresponding distortion of the supports from the spherical surface for matching the two surfaces more closely; this corresponds to the previously mentioned exception.

The drawing also illustrates the use of drum 26. This is a matter of convenience rather than necessity, and supporting of the coil form may be performed altogether by means of the spider and of the wire supports with the drum in the latter case being completely eliminated.

It is believed that the construction and operation of the jig and of the coil form will be apparent from the foregoing description. It should be understood, nevertheless, that while the invention has been shown and described in one preferred form, reasonable modification may be made without departing from the spirit of the invention as sought to be defined in the following claims.

I claim: 1

1. A jig for winding spherical radio coils including two spaced opposing wedge plates, a plurality of wire supports positioned between said wedged plates, one surface of each of said supports being a portion of a spherical surface, and a corresponding plurality of legs for said supports, said legs being attached to one of said plates and extending towards the other plate for holding said wire supports between said plates so as to form an approximately spherically-shaped wire-supporting surface during the winding operation of said coils.

2. A jig for winding spherical coils as defined in claim 1 which further includes wedging surfaces between said wedge plates and said wire supports, and mechanical instrumentalities for making rigid wedging engagement between said plates and said supports.

3. A jig for winding spherical coils as defined in claim 1 in which each of said wedge plates is provided witha beveled:surface at the: inner edge of theperiphery ofatheplate, and means for ,wedgirr'g said supports against :said surface.

': 4. ..A jig for winding spherical iradio cells as 'ildefine'd in claim 1 in whicheach of saidwedge plates isprovided witha plurality of beveled surfaces located at theinner edge of the periphery of said plates, the number of said surfaces oneach plate corresponding to the number of said sup portsand means for wedging said supports again'st said surfaces. v

-33. A jig for .winding spherical radio coils as defined'inclaim 1, which further includes beveled surfaces on said wedge plates, a longitudinally sliding-joint having a limited radial play between each wire support and .the leg holding it, and means for wedging said supports against said surfaces and fortaking up said radial play.

" 6. A jig for winding "spherical radio coils as defined in claim 1' in which each of-sai-dwire supports comprise a flat, oblong base; four sides'perpendicular to the base and to each other; and a sixth side, said sixth side being apart of a spherical surface whose center lies along the line normal to said base and passing through the geometric center point of said base- 7. A jig for winding spherical radio coils as defined in claim 1, which further includes a dovetail joint having a limited radial play between each wire support and theleg holding said support.

8. A ji for winding sperical radio coils as defined in claim 1 in which said wire supports include a groove following a helical path corresponding to the pitch of said coils, and a crossgroove crossing the center portion of one of said supports at an angle greater than said .pitch for separating said path into two spaced symmetrical halves, and for enlarging the separation between the two adjacent center-turns of said coil.

9. A jig for winding spherical radio coils as defined in claim 1, which further includes a coil N form fitting into said jig during the winding op legs and said wire supports fitting into the spaces between said bridges substantially to supplement said approximately spherically-shaped wire-supporting surface.

10. A jig for winding spherical-radio coils as defined in claim 1, which further includes a coil form fitting into said jig duringthe winding operation of said form, said form comprising a hollow cylinder and a plurality of uniformly spaced bridges fastened, to said cylinder and extending outwardly and radially therefrom, said legs and said Wire supports fitting into the spaces between said bridges to form said spherically-shaped wire-supporting surface, and means for rigidly clamping said wire supports against said plates during the wire winding operation of said coil form, and for separating said plates during the dismantling operation of said jig whereby said plates, legs, and wire supports may be separated from said .coil form, thereby transferring the wire wound on said jig to said coil form.

11-. A jig for winding wire for a spherical radio coil including two spaced opposing wedge plates, a plurality of removable wire supports each having at least two plane surfaces bound by a spherical surface having a curvature equalto that of said coil, said supports being held by said plates 4 f r o r 2,394,028 7 supports with a limited radial play, saidjoints so 'asztdform spacedispherical portions of a sin gle, substantially spherical surface corresponding to the, surface "of said coil, a pluralityof pitched grooves on the spherical surface of saids upports whereby; said supports act as bending, guiding and supporting means for said wire duringthe winding operation of said coil, a coil form fitting between said plates and-saidwire supports, said 7 lates;supporting and. aligning said form with respect ttojsaid supports during said winding op eration, and a clamping means connectedto said 7 plates, for rigidlyholding said-plates and said supports with respect to each other during said operation, said means, when unclamped upon completion of said winding, operation, enabling allowing the positioning of said suppo'rts'in such a radial relationship with respect to said 0011 form upon tightening of said clamping meanssc' as to transfer the greaterpart of the stresses due to said bending, guiding and supportingof said wire during said, winding operation away from said coil form and onto said jig.

' 13. A coil form for supporting a wire of a spherical rotor of a ,variometer, including achollow cylinder, a plurality of uniformly spaced and identicallysshapedarcuate bridges fastened to said cylinder and extending'outwardly and ra- I dially; therefrom, a plurality of identically positionedgrooves omthearcuate portions of said 

